Kayoko hadn't ridden a train in a long time when she experienced groping for the first time. Shocked and terrified, she couldn't utter a sound, yet found herself responding to the molester's actions. Overwhelmed by a mix of shame and pleasure, she climaxed repeatedly. Reuniting with her husband after so long, the groping awakened her nearly forgotten sexuality. After that day, she became consumed by fantasies of molestation, spending her days in constant masturbation. But self-pleasure alone was no longer enough. Kayoko returned to that same train, seeking a new encounter.